I will say this. At that point in the game, the Cowboys options were limited. One look at the 49ers defense on that play (a great vantage point below) and you can tell trying any route going towards the sidelines would be well defended, something they hadn't done up until that point. Even so, this is where some creative playcalling would've been a better option, something the Cowboys had shown they could do in this very game. I personally would've taken my end zone shot here since that defensive formation would've been more favorable to exploit or draw a penalty.
Also, McCarthy was correct in that there should had been no issues spotting the ball. Except he glosses over the fact that they were the ones that made the mistake by trying to do it themselves. That's something that shouldn't even require practice - and I wonder that was even practiced - because it's such a fundamental part of the game. The closest equivalent I could think of is when Kirk Cousins took a knee instead of spiking the ball and cost his team a chance to kick a field goal.